Waste disposal for additive manufacture

ABSTRACT

A waste curing device to cure waste generated by an additive manufacturing system, the waste curing device comprising: a container for receiving the waste; a movable cover positioned above the container; one or more waste nozzles mounted on the moveable cover and configured to deliver waste into the container; a static cover positioned above the container and below the movable cover; one or more curing sources mounted on the static cover and configured to provide curing radiation to cure the waste in the container; wherein the movable cover is configured to move relative to the static cover to provide an open position for the waste nozzles to deliver waste into the container, and subsequently to a closed position, to shield the waste nozzles from curing radiation.

RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.17/258,500, filed on Jan. 7, 2021, which is a National Phase of PCTPatent Application No. PCT/IL2019/050761 having International FilingDate of Jul. 8, 2019, which claims the benefit of priority under 35 USC§ 119(e) of U.S. Provisional Patent Application No. 62/695,211 filed onJul. 9, 2018. The contents of the above applications are allincorporated by reference as if fully set forth herein in theirentirety.

FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to a methodand apparatus for waste disposal in additive manufacture and, moreparticularly, but not exclusively, to effective ways of curing waste ofbuilding material for environmentally safe disposal.

Additive manufacture, is a technology which has been developed andimproved over the last two decades and is now practical and useful forindustrial applications. Additive manufacturing builds objects from thebottom-up by depositing building materials layer-by-layer, thus formingthree-dimensional (3D) objects, including objects with complexgeometries.

Some additive manufacturing techniques are carried out using buildingmaterials which are jetted in liquid form via printing head nozzles,e.g. an array of nozzles, i.e. orifices, on the orifice plate of eachprinting head to form a layer of a 3D structure that is being built. Thelayer is straightened with a roller to provide a flat and consistentlayer surface for the subsequent layer, and/or ensure a consistent layerthickness for each layer, and following straightening with the roller,the layer is cured to solidify the layer of building material.

Provision of a consistent layer surface and/or ensuring consistent layerthickness entails removal of the required amount of building materialfrom each deposited layer. The roller thus generates a significantamount of waste material, for example about 5-50% of the volume of thedeposited building material. Additional building material waste isgenerated by printing head maintenance procedures such as purging theprinting heads, e.g. jetting of building materials via all printingheads, to clear printing head nozzles of building material residue.

Waste generated by the above processes includes waste in liquid formand/or at least partially solidified form. Unsolidified, i.e.incompletely solidified building material waste is considered ahazardous substance and is required to be stored and disposed of in anenvironmentally safe manner. Therefore, such building material wastemust be disposed of using special waste disposal techniques.

Generation of a significant amount of waste material during or aftereach printing job is a considerable operational overhead andenvironmentally safe disposal is costly and strategically complicated.In some current practices such waste is collected and pumped into acontainer which, when full, is shipped to a specialized disposalfacility, which treats the waste and disposes of it in an appropriate,environmentally friendly manner.

While waste building material in liquid form (or only partiallysolidified form) is considered hazardous, fully cured building materialis generally not considered as hazardous and can be disposed of underless stringent disposal conditions. International Patent Application No.WO2017009833A1 of the same Applicant and incorporated herein byreference, discloses a waste ink collection device that collects wastebuilding material generated by the printing process, or printing headcleaning and other incidental operations, for curing and removal.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided awaste curing device to cure waste generated by an additive manufacturingsystem, the waste curing device comprising: a container for receivingthe waste; a movable cover positioned above the container; one or morewaste nozzles mounted on the moveable cover and configured to deliverwaste into the container; a static cover positioned above the containerand below the movable cover; one or more curing sources mounted on thestatic cover and configured to provide curing radiation to cure thewaste in the container; wherein the movable cover is configured to moverelative to the static cover to provide an open position for the wastenozzles to deliver waste into the container, and subsequently to aclosed position, to shield the waste nozzles from curing radiation.

Embodiments may comprise a controller configured to control relativemovement of the movable cover and to control delivery of a predeterminedamount of waste by the waste nozzles into the container.

According to a second aspect of the present invention there is provideda waste curing device to cure waste generated by an additivemanufacturing system, the waste curing device comprising: a containerfor receiving the waste; one or more curing sources configured toprovide curing radiation to cure the waste in the container; and acontroller configured to control the curing source to provide the curingradiation, and to introduce a delay between receipt of waste by thecontainer after a predetermined amount of waste has been delivered tothe container, and the operation of the curing source for the provisionof curing radiation by the one or more curing sources.

In embodiments, the predetermined amount of waste is gauged by a changein weight of the waste and/or a change of height of the waste in thecontainer.

In embodiments, the controller may operate the one or more curingsources for at least the amount of time needed to cure the predeterminedamount of waste material delivered in each delivery cycle.

According to a third aspect of the present invention there is provided amethod of curing waste generated by an additive manufacturing system,the method comprising: delivering the waste to a container via one ormore waste nozzles; providing relative movement of one or more containercovers between an open position for delivery of the waste by the wastenozzles, and a closed position for shielding the waste nozzles fromradiation; and providing curing radiation via one or more curing sourcesfor curing the waste.

The method may provide curing radiation for curing the waste after apredetermined amount of the waste has been delivered.

In embodiments, the predetermined amount of waste comprises at least oneof a weight of the waste and a height of the waste in the container.

The method may comprise introducing a time delay between delivery of thepredetermined amount of waste into the container and the provision ofthe curing radiation.

The method may comprise operating the curing sources for at least theamount of time needed to cure the predetermined amount of waste materialdelivered in each delivery cycle.

According to a fourth aspect of the present invention there is provideda slab of cured waste material generated by an additive manufacturingsystem and cured by a waste curing device, the waste material being apolymerizable building material, and the slab being at least 95%polymerized.

Unless otherwise defined, all technical and/or scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which the invention pertains. Although methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of embodiments of the invention, exemplarymethods and/or materials are described below. In case of conflict, thepatent specification, including definitions, will control. In addition,the materials, methods, and examples are illustrative only and are notintended to be necessarily limiting.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Some embodiments of the invention are herein described, by way ofexample only, with reference to the accompanying drawings. With specificreference now to the drawings in detail, it is stressed that theparticulars shown are by way of example and for purposes of illustrativediscussion of embodiments of the invention. In this regard, thedescription taken with the drawings makes apparent to those skilled inthe art how embodiments of the invention may be practiced.

In the drawings:

FIGS. 1A to 1I are schematic illustrations of exemplary additivemanufacturing systems from which the present embodiments may be obtainwaste for disposal;

FIG. 2 is a schematic illustration of a waste disposal system accordingto some embodiments of the present invention;

FIGS. 3A and 3B are schematic illustrations showing an under view of anembodiment of a static cover for the waste disposal system of FIG. 2;

FIG. 4 is a schematic illustration showing an under view of analternative embodiment of the static cover of FIGS. 3A and 3B;

FIG. 5 is a schematic illustration showing a side view of an arrangementof a movable cover and a static cover in open position, wherein thenozzles of the movable cover (as shown in FIG. 2) protrude throughopenings of the static cover;

FIG. 6 is a schematic illustration showing a side view of an arrangementof a movable cover and a static cover in open position, wherein thenozzles of the movable cover (as shown in FIG. 2) are positioned abovethe openings of the static cover;

FIG. 7 is a schematic illustration showing a side view of an arrangementof a movable cover and a static cover in closed position, wherein thenozzles of the movable cover (as shown in FIG. 2) are shielded fromcuring radiation by the static cover;

FIGS. 8A and 8B are comparative schematic illustrations showing an underview of two embodiments of a static cover, showing different alignmentsof curing lamps around the nozzle openings;

FIG. 9 is a flow diagram showing an exemplary operation of a curingsystem according to an embodiment of the present invention;

FIGS. 10A and 10B are two different perspective views of an internalcuring device according to embodiments of the present invention;

FIGS. 11A and 11B are two different perspective views of an externalcuring device intended for connection to a 3D printing device; and

FIGS. 12A-12D is a series of photographs showing slabs of cured wastematerial, produced using embodiments of the present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The present invention, in some embodiments thereof, relates to a methodand apparatus for waste disposal in additive manufacturing and, moreparticularly, but not exclusively, to effective ways of curing buildingmaterial waste for environmentally safe disposal.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not necessarily limited in itsapplication to the details of construction and the arrangement of thecomponents and/or methods set forth in the following description and/orillustrated in the drawings and/or the Examples. The invention iscapable of other embodiments or of being practiced or carried out invarious ways.

The method and system of the present embodiments manage waste generatedduring additive manufacturing of three-dimensional objects.

The additive manufacturing is typically, but not necessarily, based oncomputer object data in a layerwise manner by forming a plurality oflayers in a configured pattern corresponding to the shape of theobjects. The computer object data can be in any known format, including,without limitation, a Standard Tessellation Language (STL) or aStereoLithography Contour (SLC) format, Virtual Reality ModelingLanguage (VRML), Additive Manufacturing File (AMF) format, DrawingExchange Format (DXF), Polygon File Format (PLY) or any other formatsuitable for Computer-Aided Design (CAD).

The term “object” as used herein refers to a whole object or a partthereof.

Each layer is optionally formed by an additive manufacturing apparatuswhich scans a two-dimensional surface and patterns it. While scanning,the additive manufacturing apparatus visits a plurality of targetlocations on the two-dimensional layer or surface, and decides, for eachtarget location or a group of target locations, whether or not thetarget location or group of target locations is to be occupied bybuilding material formulation, and which type of building materialformulation is to be delivered thereto. The decision is made accordingto a computer image of the surface.

The AM may comprise three-dimensional printing, for example,three-dimensional inkjet printing. In three-dimensional inkjet printing,a building material formulation may be dispensed from a dispensing headhaving a set of nozzles to deposit building material formulation inlayers on a supporting structure. The AM apparatus thus dispensesbuilding material formulation in target locations which are to beoccupied and leaves other target locations void. The AM apparatustypically includes a plurality of dispensing heads, each of which can beconfigured to dispense a different building material formulation. Thus,different target locations can be occupied by different buildingmaterial formulations. The types of building material formulations canbe categorized into two major categories: modeling material formulationand support material formulation. The support material formulationserves for building a matrix or construction for supporting the objector object parts during the fabrication process and/or other purposes,e.g., providing hollow or porous objects. Support constructions mayadditionally include modeling material formulation elements, e.g. forfurther support strength.

The modeling material formulation is generally a composition which isformulated for use in additive manufacturing and which is able to form athree-dimensional object on its own, i.e., without having to be mixed orcombined with any other substance.

The final three-dimensional object is made of the modeling materialformulation or a combination of modeling material formulations ormodeling and support material formulations or modification thereof(e.g., following curing). All these operations are well-known to thoseskilled in the art of solid freeform fabrication.

The AM system may optionally, but not necessarily, manufacture an objectby dispensing two or more different modeling material formulations, eachmaterial formulation being dispensed from a different dispensing head orfrom a different channel of the dispensing head of the AM system. Thematerial formulations can be deposited in layers during the same pass ofthe printing heads. The material formulations and combination ofmaterial formulations within the layer can be selected according to thedesired properties of the object.

A representative and non-limiting example of a system 110 suitable forAM of an object 112 is illustrated in FIG. 1A. System 110 comprises anadditive manufacturing apparatus 114 having a dispensing unit 16 whichcomprises a plurality of dispensing heads. Each head preferablycomprises an array of one or more nozzles 122, as illustrated in FIGS.1E-G described below, in fluid connection with one or more channels (notshown), through which a liquid building material formulation 124 isdispensed.

AM apparatus 114 can be a three-dimensional printing apparatus, in whichcase the dispensing heads are printing heads, and the building materialformulation is dispensed via inkjet technology. This need notnecessarily be the case, since, for some applications, it may not benecessary for the additive manufacturing apparatus to employthree-dimensional printing techniques. Representative examples ofadditive manufacturing apparatus contemplated according to variousexemplary embodiments of the present invention include, withoutlimitation, fused deposition modeling apparatus and fused materialformulation deposition apparatus.

Each dispensing head can be fed via one or more building materialformulation reservoirs which may optionally include a temperaturecontrol unit (e.g., a temperature sensor and/or a heating device), and amaterial formulation level sensor. To dispense the building materialformulation, a voltage signal can be applied to the dispensing heads toselectively deposit droplets of material formulation via the dispensinghead nozzles, for example, as in piezoelectric inkjet printingtechnology. The dispensing rate of each head depends on the number ofnozzles, the type of nozzles and the applied voltage signal rate(frequency). Such dispensing heads are known to those skilled in the artof solid freeform fabrication.

Preferably, but not obligatorily, the overall number of dispensingnozzles or nozzle arrays can be selected such that half of thedispensing nozzles are designated to dispense support materialformulation and half of the dispensing nozzles are designated todispense modeling material formulation, i.e. the number of nozzlesjetting modeling material formulations is the same as the number ofnozzles jetting support material formulation. In the representative andnon-limiting example of FIG. 1A, four dispensing heads 16 a, 16 b, 16 cand 16 d are illustrated. Each of heads 16 a, 16 b, 16 c and 16 d has anozzle array. In this Example, heads 16 a and 16 b can be designated formodeling material formulation/s and heads 16 c and 16 d can bedesignated for support material formulation. Thus, head 16 a candispense one modeling material formulation, head 16 b can dispenseanother modeling material formulation and heads 16 c and 16 d can bothdispense support material formulation. In an alternative embodiment,heads 16 c and 16 d, for example, may be combined in a single headhaving two nozzle arrays for depositing support material formulation. Insome other embodiments, heads 16 a and 16 b are combined into a singledual channel print head that dispenses two distinct modeling materialformulations, and heads 16 c and 16 d are combined into a single dualchannel print head that dispenses one or more support materialformulations.

Yet it is to be understood that it is not intended to limit the scope ofthe present invention and that the number of modeling materialformulation depositing heads (modeling heads) and the number of supportmaterial formulation depositing heads (support heads) may differ.Generally, the number of modeling heads, the number of support heads andthe number of nozzles in each respective head or head array are selectedsuch as to provide a predetermined ratio, a, between the maximaldispensing rate of the support material formulation and the maximaldispensing rate of modeling material formulation. The value of thepredetermined ratio, a, is preferably selected to ensure that in eachformed layer, the height of modeling material formulation equals theheight of support material formulation. Typical values for a are fromabout 0.6 to about 1.5. It is further to be understood that it is notnecessary for an AM apparatus to be a multi-material AM apparatus, andfor a multi-material AM apparatus to have half of the dispensing nozzlesfor dispensing support material formulation and half of the dispensingnozzles for dispensing modeling material formulation.

It is known to the skilled artisan that the type of print heads (e.g.single channel or multiple channel) and the number of print heads usedin an AM system as described above may be adapted according to severalconsiderations such as (1) the number and the nature of the buildingmaterial formulations used in the AM system; (2) the printing resolutionrequirement for each one of the formulations; and (3) the overallprinting speed to be achieved.

The dispensing head and radiation source are preferably mounted in aframe or block 128 which is preferably operative to reciprocally moveover a tray 360, which serves as the working surface. In someembodiments of the present invention the radiation sources are mountedin the block such that they follow in the wake of the dispensing headsto at least partially cure or solidify the material formulations justdispensed by the dispensing heads. Tray 360 is positioned horizontally.According to the common conventions an X-Y-Z Cartesian coordinate systemis selected such that the X-Y plane is parallel to tray 360. Tray 360 ispreferably configured to move vertically (along the Z direction, alsoreferred to as the built direction), typically downward. In variousexemplary embodiments of the invention, AM apparatus 114 furthercomprises one or more leveling devices 132, e.g. a roller 326. Levelingdevice 326 serves to straighten, level and/or establish a thickness ofthe newly formed layer prior to the formation of the successive layerthereon. AM apparatus 114 optionally and preferably comprises a wastecollection device 136 for collecting the excess material formulationgenerated during leveling. A waste collection device 136 suitable forthe present embodiments is described below.

In use, the dispensing heads of unit 16 move in a scanning direction,which is referred to herein as the X direction, and selectively dispensebuilding material formulation in a predetermined configuration in thecourse of their passage over tray 360. The building material formulationtypically comprises one or more types of support material formulationand one or more types of modeling material formulation. The passage ofthe dispensing heads of unit 16 is followed by the curing of themodeling material formulation(s) by radiation source 126. In the reversepassage of the heads, back to their starting point for the layer justdeposited, an additional dispensing of building material formulation maybe carried out, according to a predetermined configuration. In theforward and/or reverse passages (or passes) of the dispensing heads, thelayer thus formed may be straightened by leveling device 326, whichpreferably follows the path of the dispensing heads in their forwardand/or reverse movement. Once the dispensing heads return to theirstarting point along the X direction, they may move to another positionalong an indexing direction, referred to herein as the Y direction, andcontinue to build the same layer by reciprocal movement along the Xdirection. Alternately, the dispensing heads may move in the Y directionbetween forward and reverse movements or after more than oneforward-reverse movement. The series of scans performed by thedispensing heads to complete a single layer is referred to herein as asingle scan cycle.

Once the layer is completed, tray 360 is lowered in the Z direction to apredetermined Z level, according to the desired thickness of the layersubsequently to be printed. The procedure is repeated to formthree-dimensional object 112 in a layerwise manner.

In another embodiment, tray 360 may be displaced in the Z directionbetween forward and reverse passages of the dispensing head of unit 16,within the layer. Such Z displacement is carried out in order to causecontact of the leveling device with the surface in one direction andprevent contact in the other direction.

System 110 optionally and preferably comprises a building materialformulation supply system 330 which comprises the building materialformulation containers or cartridges and supplies a plurality ofbuilding material formulations to AM apparatus 114.

Another representative and non-limiting example of a system 10 fromwhich the present embodiments may be obtain waste for disposal isillustrated in FIGS. 1B-D. FIGS. 1B-D illustrate a top view (FIG. 1B), aside view (FIG. 1C) and an isometric view (FIG. 1D) of system 10.

System 10 comprises a tray 12 and a plurality of inkjet printing heads16, each having a plurality of separated nozzles. Tray 12 can have ashape of a disk or it can be annular. Non-round shapes are alsocontemplated for system 10.

Tray 12 and heads 16 of system 10 are optionally mounted such as toallow a relative rotary motion between tray 12 and heads 16. This can beachieved by (i) configuring tray 12 to rotate about a vertical axis 14relative to heads 16, (ii) configuring heads 16 to rotate about verticalaxis 14 relative to tray 12, or (iii) configuring both tray 12 and heads16 to rotate about vertical axis 14 but at different rotation velocities(e.g., rotation at opposite direction). While the embodiments below aredescribed with a particular emphasis to configuration (i) wherein thetray is a rotary tray that is configured to rotate about vertical axis14 relative to heads 16, it is to be understood that the presentapplication contemplates also configurations (ii) and (iii). Any one ofthe embodiments described herein can be adjusted to be applicable to anyof configurations (ii) and (iii), and one of ordinary skills in the art,provided with the details described herein, would know how to make suchadjustment.

In the following description, a direction parallel to tray 12 andpointing outwardly from axis 14 is referred to as the radial directionr, a direction parallel to tray 12 and perpendicular to the radialdirection r is referred to herein as the azimuthal direction j, and adirection perpendicular to tray 12 is referred to herein is the verticaldirection z.

The term “radial position,” as used herein, refers to a position on orabove tray 12 at a specific distance from axis 14. When the term is usedin connection to a printing head, the term refers to a position of thehead which is at specific distance from axis 14. When the term is usedin connection to a point on tray 12, the term corresponds to any pointthat belongs to a locus of points that is a circle whose radius is thespecific distance from axis 14 and whose center is at axis 14.

The term “azimuthal position,” as used herein, refers to a position onor above tray 12 at a specific azimuthal angle relative to apredetermined reference point. Thus, radial position refers to any pointthat belongs to a locus of points that is a straight line forming thespecific azimuthal angle relative to the reference point.

The term “vertical position,” as used herein, refers to a position overa plane that intersect the vertical axis 14 at a specific point.

Tray 12 serves as a supporting structure for three-dimensional printing.The working area on which one or objects are printed is typically, butnot necessarily, smaller than the total area of tray 12. In someembodiments of the present invention the working area is annular. Theworking area is shown at 26. In some embodiments of the presentinvention tray 12 rotates continuously in the same direction throughoutthe formation of object, and in some embodiments of the presentinvention tray reverses the direction of rotation at least once (e.g.,in an oscillatory manner) during the formation of the object. Tray 12 isoptionally and preferably removable. Removing tray 12 can be formaintenance of system 10, or, if desired, for replacing the tray beforeprinting a new object. In some embodiments of the present inventionsystem 10 is provided with one or more different replacement trays(e.g., a kit of replacement trays), wherein two or more trays aredesignated for different types of objects (e.g., different weights)different operation modes (e.g., different rotation speeds), etc. Thereplacement of tray 12 can be manual or automatic, as desired. Whenautomatic replacement is employed, system 10 comprises a trayreplacement device 36 configured for removing tray 12 from its positionbelow heads 16 and replacing it by a replacement tray (not shown). Inthe representative illustration of FIG. 1B tray replacement device 36 isillustrated as a drive 38 with a movable arm 40 configured to pull tray12, but other types of tray replacement devices are also contemplated.

Examples for the printing head 16 are illustrated in FIGS. 1E-1G. Suchheads can be employed for any of the AM systems described above,including, without limitation, system 110 and system 10.

FIGS. 1E and 1F illustrate a printing head 16 with one (FIG. 1E) and two(FIG. 1F) nozzle arrays 22. The nozzles in the array are preferablyaligned linearly, along a straight line. When a particular printing headhas two or more linear nozzle arrays, the nozzle arrays are optionallyparallel to each other.

When a system similar to system 110 is employed, all printing heads 16are optionally and preferably oriented along the indexing direction withtheir positions along the scanning direction being offset to oneanother.

When a system similar to system 10 is employed, all printing heads 16are optionally and preferably oriented radially (parallel to the radialdirection) with their azimuthal positions being offset to one another.Thus, for such a system the nozzle arrays of different printing headsare not parallel to each other but are rather at an angle to each other,which angle being approximately equal to the azimuthal offset betweenthe respective heads. For example, one head can be oriented radially andpositioned at azimuthal position j₁, and another head can be orientedradially and positioned at azimuthal position j₂. In this example, theazimuthal offset between the two heads is j₁-j₂, and the angle betweenthe linear nozzle arrays of the two heads is also j₁-j₂.

Optionally, two or more printing heads can be assembled to a block ofprinting heads, in which case the printing heads of the block aretypically parallel to each other. A block including several inkjetprinting heads 16 a, 16 b, 16 c is illustrated in FIG. 1G.

Optionally, system 10 comprises a stabilizing structure 30 positionedbelow heads 16 such that tray 12 is between stabilizing structure 30 andheads 16. Stabilizing structure 30 may serve for preventing or reducingvibrations of tray 12 that may occur while inkjet printing heads 16operate. In configurations in which printing heads 16 rotate about axis14, stabilizing structure 30 preferably also rotates such thatstabilizing structure 30 is always directly below heads 16 (with tray 12between heads 16 and tray 12).

Tray 12 and/or printing heads 16 is optionally configured to move alongthe vertical direction z, parallel to vertical axis 14 so as to vary thevertical distance between tray 12 and printing heads 16. Inconfigurations in which the vertical distance is varied by moving tray12 along the vertical direction, stabilizing structure 30 preferablyalso moves vertically together with tray 12. In configurations in whichthe vertical distance is varied by heads 16 along the verticaldirection, while maintaining the vertical position of tray 12 fixed,stabilizing structure 30 is also maintained at a fixed verticalposition.

The vertical motion can be established by a vertical drive 28. Once alayer is completed, the vertical distance between tray 12 and heads 16can be increased (e.g., tray 12 is lowered relative to heads 16) by apredetermined vertical step, according to the desired thickness of thelayer subsequently to be printed. The procedure is repeated to form athree-dimensional object in a layerwise manner.

System 10 may comprise one or more leveling devices 32 which can bemanufactured as a roller or a blade. Leveling device 32 serves tostraighten the newly formed layer prior to the formation of thesuccessive layer thereon. Leveling device 32 may have the shape of aconical roller positioned such that its symmetry axis 34 is tiltedrelative to the surface of tray 12 and its surface is parallel to thesurface of the tray, as illustrated in the side view of system 10 (FIG.1C).

The conical roller can have the shape of a cone or a conical frustum.

The opening angle of the conical roller is preferably selected such thatis a constant ratio between the radius of the cone at any location alongits axis 34 and the distance between that location and axis 14. Thisembodiment allows roller 32 to efficiently level the layers, since whilethe roller rotates, any point p on the surface of the roller has alinear velocity which is proportional (e.g., the same) to the linearvelocity of the tray at a point vertically beneath point p. In someembodiments, the roller has a shape of a conical frustum having a heighth, a radius R₁ at its closest distance from axis 14, and a radius R₂ atits farthest distance from axis 14, wherein the parameters h, R₁ and R₂satisfy the relation R₁/R₂=(R−h)/h and wherein R is the farthestdistance of the roller from axis 14 (for example, R can be the radius oftray 12).

System 10 optionally and preferably comprises a waste collection device136 for collecting the excess material formulation generated duringleveling. A waste collection device 136 suitable for the presentembodiments is described below.

In system 10, printing heads 16 can be configured to reciprocally moverelative to tray along the radial direction r. These embodiments areuseful when the lengths of the nozzle arrays 22 of heads 16 are shorterthan the width along the radial direction of the working area 26 on tray12. The motion of heads 16 along the radial direction is optionally andpreferably controlled by controller 20.

Any of systems 10 and 110 may optionally comprise a solidifying device18 which can include any device configured to emit light, heat or thelike that may cause the deposited material formulation to harden. Forexample, solidifying device 18 can comprise one or more radiationsources, which can be, for example, an ultraviolet or visible orinfrared lamp, or other sources of electromagnetic radiation, orelectron beam source, depending on the modeling material formulationbeing used. The radiation source can include any type of radiationemitting device, including, without limitation, light emitting diode(LED), digital light processing (DLP) system, resistive lamp and thelike. In some embodiments of the present invention, solidifying device18 serves for curing or solidifying the modeling material formulation.

In any of systems 10 and 110, the operation of the inkjet printing headsand optionally and preferably also of one or more other components ofthe system, e.g., the motion of the tray, the operation of the supplysystem, the operation of the waste collection device, the activation,deactivation, applied voltage, and position along the vertical and/orhorizontal direction of the leveling device and/or the solidifyingdevice, etc. are controlled by a controller (shown at 20). Thecontroller can have an electronic circuit and a non-volatile memorymedium readable by the circuit, wherein the memory medium stores programinstructions which, when read by the circuit, cause the circuit toperform control operations as further detailed below.

The controller preferably communicates with a data processor or hostcomputer (shown at 24) which transmits digital data pertaining tofabrication instructions based on computer object data, e.g., aComputer-Aided Design (CAD) configuration represented on a computerreadable medium in a form of a Standard Tessellation Language (STL) or aStereoLithography Contour (SLC) format, Virtual Reality ModelingLanguage (VRML), Additive Manufacturing File (AMF) format, DrawingExchange Format (DXF), Polygon File Format (PLY) or any other formatsuitable for CAD. Typically, the controller controls the voltage appliedto each dispensing head or nozzle array and the temperature of thebuilding material formulation in the respective printing head.Generally, controller 20 controls printing heads to dispense, dropletsof building material formulation in layers, such as to print athree-dimensional object. In system 10, controller 20 optionally andpreferably controls the printing heads to dispense the droplets whilethe tray is rotating.

In some embodiments, the controller receives additional input from theoperator, e.g., using data processor 24 or using a user interface 116communicating with the controller. User interface 116 can be of any typeknown in the art, such as, but not limited to, a keyboard, a touchscreen and the like. For example, controller 20 can receive, asadditional input, one or more building material formulation types and/orattributes, such as, but not limited to, color, characteristicdistortion and/or transition temperature, viscosity, electricalproperty, magnetic property. Other attributes and groups of attributesare also contemplated.

The object data formats are typically structured according to aCartesian system of coordinates. In these cases, when system 10 isemployed, computer 24 preferably executes a procedure for transformingthe coordinates of each slice in the computer object data from aCartesian system of coordinates into a polar system of coordinates.Computer 24 optionally and preferably transmits the fabricationinstructions in terms of the transformed system of coordinates.Alternatively, computer 24 can transmit the fabrication instructions interms of the original system of coordinates as provided by the computerobject data, in which case the transformation of coordinates is executedby the circuit of controller 20.

The transformation of coordinates allows three-dimensional printing overa rotating tray. In system 10, not all the nozzles of the head pointscover the same distance over tray 12 during at the same time. Thetransformation of coordinates is can be executed so as to ensure equalamounts of excess material formulation at different radial positions.Representative examples of coordinate transformations are provided inFIGS. 1H and 1I, showing three slices of an object (each slicecorresponds to fabrication instructions of a different layer of theobjects), where FIG. 1H illustrates a slice in a Cartesian system ofcoordinates and FIG. 1I illustrates the same slice following anapplication of a transformation of coordinates procedure to therespective slice.

The AM system can fabricate an object by dispensing different materialformulations from different dispensing heads. These embodiments provide,inter alia, the ability to select material formulations from a givennumber of material formulations and define desired combinations of theselected material formulations and their properties. According to thepresent embodiments, the spatial locations of the deposition of eachmaterial formulation with the layer is defined, either to effectoccupation of different three-dimensional spatial locations by differentmaterial formulations, or to effect occupation of substantially the samethree-dimensional location or adjacent three-dimensional locations bytwo or more different material formulations so as to allow postdeposition spatial combination of the material formulations within thelayer, thereby to form a composite material formulation at therespective location or locations.

Any post deposition combination or mix of modeling material formulationsis contemplated. For example, once a certain material formulation isdispensed it may preserve its original properties. However, when it isdispensed simultaneously with another modeling material formulation orother dispensed material formulations which are dispensed at the same ornearby locations, a composite material formulation having a differentproperty or properties to the dispensed material formulations is formed.

An AM system that can fabricate an object by dispensing differentmaterial formulations enable the deposition of a broad range of materialformulation combinations, and the fabrication of an object which mayconsist of multiple different combinations of material formulations, indifferent parts of the object, according to the properties desired tocharacterize each part of the object.

Further details on the principles and operations of an AM system fromwhich the present embodiments may be obtain waste for disposal are foundin U.S. Published Application Nos. 20100191360 and 20170173886, thecontents of which are hereby incorporated by reference.

As explained, building material waste, which may be modeling materialand/or support material, and generally consists of uncured and/orpartially cured polymer, is a hazardous material and must be disposed ofusing environmentally safe waste disposal techniques. The 3D printingprocess generates a significant amount of waste, typically about 5-50%of the volume jetted by the heads. Additional waste is also generated byhead maintenance procedures such as purging.

While the waste in liquid and/or partially cured form is consideredhazardous, fully cured waste is not generally considered as hazardousand may be disposed of under less stringent disposal conditions.International Patent Application No. WO2017009833 supra, discloses awaste collection technique in which the waste is stored and cured. Thewaste drips into a waste disposal container through waste dedicatednozzles and then UV radiation is used to cure the waste. It was found bythe inventors that, UV light is liable to reflect onto the waste nozzlesand cause polymerization of the waste material in the vicinity of thenozzles and thus hinder the flow of waste material through the nozzles.For example, building material, in the process of dripping through thenozzles as the UV light is operated may form “stalactites” of curedmaterial (due to UV reflection) and besides causing obstruction of thenozzles, may affect curing efficiency by creating shadows that obstructUV exposure in some regions of the container. Additionally, disposal ofthe waste container after curing assumes that the waste is fully cured.If, however, the rate of accumulation of uncured waste at some point inthe process becomes more rapid than the rate of waste curing, then atleast part the waste will not be fully cured.

The present embodiments aim to solve the above problems by timing theoperation of curing energy, for example UV light, according to theamount of building material waste being generated, and by shielding thewaste nozzles during operation of the UV light source/s. It was foundthat stalactite formation may be generally prevented by introducing asmall delay between the steps of dripping waste into the container andthe commencement of UV operation, while shielding the nozzles from UVexposure.

In some embodiments, a UV light-based curing process may be carried outevery time a given, predetermined amount of waste has been pumped intothe waste container, or every time a preset number of pumping operationshas occurred.

According to the present embodiments, following curing, the wastebuilding material forms a solid mass and as such is generally no longerconsidered hazardous, and may be disposed of under less stringentdisposal conditions.

Thus the present embodiments may carry out a procedure in which theamount of waste fed into the waste container is predetermined andmeasured. Once a predetermined amount of the uncured waste material hasbeen pumped into the waste container, then waste feeding is stopped. Adelay is introduced to allow dripping to cease. The waste nozzles aremoved horizontally to a shielded position and a further delay isintroduced to allow for the waste material to spread within thecontainer and reach an equilibrium. Curing energy is then initiated andis provided for at least the amount of time needed to cure thepredetermined amount of waste material deposited during the currentcycle. Curing is then stopped and the waste nozzles are movedhorizontally back into their original position and feeding of the nextpredetermined amount of waste is initiated.

For the purposes of the waste curing procedure, a feed device providesthe waste building material to a waste container. The feed device mayinclude a pump, a distribution system for distributing the waste towaste nozzles, and waste nozzles mounted on a moveable cover. When thewaste material is to be injected into the waste container, the wastenozzles are positioned above or within openings located in a staticcover beneath the movable cover. During the curing step, the wastenozzles are shielded by the static cover, at a horizontal distance fromthe openings. In some embodiments the cover upon which the nozzles aremounted is movable relative to a static cover having openings, while inother embodiments the nozzles are mounted to a static cover and thecover having openings is movable relative thereto.

In some embodiments, the waste nozzles are inserted i.e. protrudethrough the openings, while in other embodiments waste nozzles arepositioned above the openings. Curing energy may be provided by LEDlamps mounted on the static cover and positioned at a distance from eachopening for example to prevent them being stained by waste exiting thenozzles.

Reference is now made to FIG. 2, which is a schematic illustrationshowing a waste disposal system for an additive manufacturing apparatusaccording to embodiments of the present invention. As discussed abovewith respect to FIG. 1A, additive manufacturing apparatus 114 comprisesone or more leveling devices 132 such as a roller 326. Leveling device326 serves to straighten, level and/or establish a thickness of eachnewly formed layer prior to the formation of the successive layerthereon. Leveling device i.e. roller 326 is associated with a wastecollection device 136 for collecting excess building material duringleveling. Waste collection device 136 may comprise any mechanism thatcollects excess building material removed by the roller during leveling,and then transfers the collected waste material to a waste curing device600. In some embodiments, waste curing device 600 comprises a wastecontainer 400 wherein waste material 404 is being cured, and a wastefeeding and curing device 402 comprising a waste distribution system413, a movable cover 424 upon which are mounted feeding nozzles 420, astatic cover 426 having openings (not shown) and upon which are mountedenergy sources, such as light emitting diodes 410.

Waste curing device 600 may be an integral part of a 3D printer or maybe an external device connected to a 3D printer for example via a pipe,to handle waste generated by the printer. When part of the 3D printer,waste curing device 600 may share a controller with the 3D printer,while if external, an independent controller may be used to controlwaste curing device 600 separately from the 3D printer.

Waste curing device 600 is in fluid connection with the waste generatingelements 412 of the 3D printer, which may include, without limitation,roller 326 of FIG. 1A and a purging system for purging of printing heads(not shown). Waste material collected from waste generating elements 412may be directly transferred to waste curing device 600 or temporarilystored in an intermediate waste material collector (not shown). Then,the waste material is transferred to feeding and curing system 402 viadistribution system 413 which comprises waste pump 414, check valvesystem 416, tubing 418, and waste nozzles 420. Container 400 may be inthe form of a removable cartridge. In some embodiments, distributionsystem 413, may have a shower head construction, and may distribute thewaste from inlets via tubing 418 to waste nozzles 420 distributed evenlyover the surface area of the waste container 400. The idea is todispense waste evenly over the surface of the container, as will beexplained in greater detail below.

Waste curing device 600, as mentioned, cures the waste upon collection.In some embodiments, curing of the waste material 404 in waste container400 is not performed simultaneously with the delivery of waste material404 into waste container 400, but rather, the collection of waste uses aprocess which is controlled by a controller such as controller 152 inFIG. 1A. The controller may operate distribution system 413 of curingdevice 600 after a specified and predetermined amount of waste material404 has been delivered to waste container 400. Thus, while delivering ordepositing waste material 404, the energy source(s) 410 are turned off,and a predetermined amount of waste material 404 is delivered intocontainer 400. After the predetermined amount of waste material 404 hasbeen delivered, delivery or pumping of waste material is halted. After apredetermined delay, curing sources 410 are turned on for a specifiedamount of time needed to cure the delivered amount of waste. Curing isthen halted again and delivery is resumed, until either the container isfull or the container contains a specified amount of waste. Thus eachpredetermined amount of waste receives a constant and predeterminedamount of curing energy, and thus waste collection and fullsolidification becomes more scalable for different speeds of operationand rates of waste production. In embodiments, timed delays may beintroduced into the procedure, as will be discussed in greater detailhereinbelow.

In some embodiments, waste pump 414 may pump waste material directlyfrom the waste generating elements 412 of the 3D printer or from anintermediate waste material collector. Check valve 416 may optionally beprovided at the head of tubing system 418 which consists of a series ofdistribution pipes that feed waste nozzles 420 evenly distributed on amoveable cover 424. In FIG. 2, four waste nozzles 420A . . . 420D areshown by way of example but in practice a number of waste insertionnozzles is selected that is sufficient to ensure even distribution ofthe waste over the container. It is noted that in some embodiments thewaste nozzles are simple drip nozzles, and in other embodiments arejet-forming nozzles of the kind that may be found on inkjet printingheads and which jet the waste into the tank.

In some embodiments, the specified amount of waste material that isdelivered between each curing operation may be determined according to anumber of pumping operations of pump 414. Alternatively, the number ofwaste jetting operations may be counted. As a third alternative, wastecontainer 400 may be continually weighed and a specified change inweight may be gauged. As a further possibility, the height of the waste404 in the container 400 may be used and a predetermined change inheight may be used to indicate when delivery of waste is to be haltedand for curing to begin. The skilled person will be able to findadditional ways of measuring the amount of waste that has beencollected.

Thus waste is delivered to waste container 400 via waste nozzles 420when the waste nozzles are in open position, i.e. exposed above thecontainer. The waste nozzles may then be closed in order to halt furtherdelivery of waste during the curing process. The controller may operateactuators or a motor 422 in order to change the location of nozzles 420and move them from an open to a close position (and vice versa) atsuitable times. Shielding waste nozzles 420 from energy source(s) 410during curing (e.g. with static cover 426) protects waste nozzles 420from energy radiations which otherwise might have cured waste materialstill present in the waste nozzles, thus blocking the nozzles.

As illustrated in the embodiment shown in FIG. 2, waste nozzles 420 aremounted on movable cover 424 which may be moved horizontally in asliding motion powered by motor 422. A static cover 426 positionedunderneath the movable cover has openings with which waste nozzles 420may be aligned when dripping waste material. The movable cover slidesbetween a first position where the waste nozzles are aligned with theopenings to provide the waste nozzle open position, and a secondposition in which the waste nozzles are not aligned with the openings,i.e. are distanced from the openings, to give a waste nozzle closedposition (and shielded from curing sources). In an embodiment, themovable cover is also able to move vertically towards the static coverso that the waste nozzles may be inserted through and thus protrudethrough the openings.

As an alternative, it is possible to provide the openings in a movablecover and to mount the waste insertion nozzles on a static cover. Theeffect is still the same, and the nozzles are aligned with the openingswhen in open position and shielded from stray radiation in the closedposition.

Waste curing device 402 includes energy/curing sources 410 which arepreferably evenly distributed over waste container 400. Curing sources410 may typically be LEDs that generate an energy via UV light. The LEDsmay be provided as banks or strips. The LEDs may be offset from thewaste nozzles or nozzle openings, as will be discussed in greater detailbelow.

Reference is now made to FIGS. 3A and 3B which are two schematicillustrations of the underside of a static cover of a waste curingdevice according to an embodiment of the invention in which three LEDstrips 430 are used. In order to accommodate the three strips, openings432 for the insertion of waste nozzles are provided in two rows in thegaps between the strips. Thus the strips with the LEDs are not alignedin the width direction with the openings for the waste insertionnozzles. FIG. 3B shows the strips and openings schematically and FIG. 3Ashows the positions of individual LED lamps 434 along the strips.

FIG. 4 is a variation of FIGS. 3A and 3B in which a single line ofnozzle openings 432 is shown. The LEDs 434 are individual LED lampsfitted onto a board and are positioned around each opening.

In some embodiments, preferably and typically, the size of the openings432 is larger than the tips of the waste nozzles, and sufficiently largeto ensure that material dripping or jetted from the waste nozzles fallsthrough the openings and is not sprayed onto the cover surface.

In some embodiments, the nozzle openings have a maximum diameter of 2mm. Such a maximum diameter makes it easier to control the amount ofwaste jetted in each cycle, which is useful particularly if the numberof jetting operations is being used to measure the quantity of wastebeing collected. Furthermore, such a size assists with pulse formationto form a burst of waste.

Reference is now made to FIGS. 5-7 which show side views of successivepositions of the static 426 and movable 424 covers over the course of acycle according to embodiments of the present invention. FIG. 5 shows ajetting position used in some embodiments of the present invention inwhich the waste nozzles 420 in the movable cover 424 are aligned withrespective openings 432 in the static cover, and the movable cover isthen moved into proximity with the static cover such that the wastenozzles 420 are inserted through the openings 432. The advantage is thatthe jets of material are delivered from a position that is clear of theLED lamps 410 and thus contamination of the LED lamps by spraying ofwaste material is kept to a minimum.

In FIG. 6 the movable cover 424 has been raised so that the wastenozzles are not inserted in the opening, thus allowing the movable coverto be moved sideways. In some embodiments, where the movable cover isonly movable horizontally, the position shown in FIG. 6 is the openposition that is used for jetting or pumping the waste material into thecontainer 400, and there is no equivalent of the FIG. 5 position. Thusdepending on the embodiment, either FIG. 5 or FIG. 6 represent an openposition. The skilled person will bear in mind that additionalembodiments are contemplated in which the cover with the waste insertionnozzles is static and the cover with the openings is a movable cover.

FIG. 7 illustrates the closed position. Movable cover 424 has been movedin a horizontal direction such that the waste nozzles 420 are no longeraligned with openings 432 in the static cover. The static cover nowserves as a shield to protect the waste nozzles from reflection of thecuring radiation. Dotted lines 440 indicate a passage of light of thecuring radiation onto the waste in container 400 and its possible atleast partial reflection back towards the openings 432. The tips of thewaste nozzles are located close to the top surface of static cover 426and are thus shielded from stray radiation.

Reference is now made to FIGS. 8A and 8B, which show two slightlydifferent layouts for LED lamps around openings in the underside ofstatic cover 426. In FIG. 8A, some of the LEDs 434 are in closeproximity to the openings 432, and in FIG. 8B the LEDs are equallydistanced from the openings. An advantage of the latter embodiment, isthat the LED lamps are less exposed to waste splashing from the nozzles.

Reference is now made to FIG. 9 which is a simplified flow chartillustrating operation of the waste collection and curing system. Inuse, as mentioned above, the controller may operate the waste curingdevice 600 on each occasion that a specified amount of waste has beengenerated by the waste generating elements 412 of the 3D printer. Thus,the system is initialized 500 and the movable cover is moved to the openposition 502. A delay may be introduced between switching to an openingposition and the beginning of delivery of waste material into the wastecontainer, the delay being shown as half a second by way of example.Delivery of waste material into the waste container is carried out 504,and while delivering, the energy sources are turned off, and thespecified amount of waste material is accumulated in the wastecontainer. Delivery of waste material via the waste nozzles can be donesimultaneously or sequentially. In some embodiments, sequential deliveryis selected so as to allow an equivalent amount of waste material to befed via each nozzle and enable faster and more even spreading of thewaste material in the container. Delivery is then halted and the coversare moved relative to each other to a closed position 506, therebyclosing the openings and shielding the waste nozzles. In someembodiments, a delay is introduced at this point, to provide timebetween the end of waste delivery into the waste container and the startof curing, for the uncured waste newly accumulated in the container tospread out evenly in the container 508. Here by way of example the delayis shown to be half a second to allow drips to cease and the cover toclose followed by a second delay of 15 seconds for the material tospread. Allowing the drips to complete may prevent formation ofstalactites, and allowing the waste to spread may prevent lumps thatonly get partially cured because the radiation fails to reach inside thelump. Furthermore, a smooth surface is left for the next step, removingshadows and helping with even spreading of the next round of ink.

After the delay, energy sources (e.g. LEDs) are turned on 510 for aspecific amount of time adequate to fully cure the new layer ofaccumulated waste—here shown by way of example as 60 seconds. Curingtime can be adjusted according to the type of waste material being curedand the amount of material delivered into the container in each cycle.Then energy sources are turned off 512 and the total amount of materialaccumulated in the container is sampled or measured 514. If thecontainer is full 516 then the procedure ends 518. If not, the deliveryand curing cycle is repeated from 502. In some embodiments, a deliveryand curing cycle takes about 1.5 min and an amount of waste materialdelivered and cured in a cycle is about 3 to 10 g. An exemplary rate ofwaste delivery and curing is about 120 to 400 g per hour, for instance155 g/h.

Thus, irrespective of whether waste delivery is fast or slow, the sameamount of waste receives the same amount of curing energy, and wastedelivery in general becomes scalable for different speeds of operationand different rates of waste production.

Reference is now made to FIGS. 10A and 10B, which are schematicillustrations showing an embodiment of an internal waste curing device600 from side and front perspective views respectively. The device 600is fitted internally into a 3D printer and includes waste inlets 532 forflow of waste. Motor housing 534 houses motor 422 (see FIG. 2) thatmoves movable cover 424 and the energy sources (e.g. LEDs) 410 can beseen in strips 430 on the underside of the static cover 426 along withopenings 432 for the waste nozzles. Waste collection containers areinserted into container compartment 546 and replaced when full.

FIG. 11A and FIG. 11B show two different perspective views of anexternal waste curing device according to another embodiment of theinvention. The external device is an add-on for an existing 3D printerand may be connected to a pipe that leads to the internal waste materialcollector of the printer. Alternatively, the waste material collector ofthe 3D printer is taken out of the printer and connected to the externalwaste curing device, while a new waste material collector is insertedinto the 3D printer.

FIGS. 12A-12D are a series of photographs of the end result of thecurrent process, in which slabs of cured waste material are shown. Morespecifically, FIG. 12A shows a slab of cured waste material in adisposable container; FIG. 12B shows a slab of cured waste materialafter being removed from its container; FIG. 12C shows a slab of curedwaste material from which a cylindrical sample was taken to determinethe degree of curing; FIG. 12D shows a number of slabs of cured wastematerial each of which was generated by a different combination ofbuilding materials. Each of the masses or slabs may be at least 95%cured.

It is expected that during the life of a patent maturing from thisapplication many relevant additive manufacturing and curing technologieswill be developed and the scopes of the terms “additive manufacture” and“curing” are intended to include all such new technologies a priori.

The terms “comprises”, “comprising”, “includes”, “including”, “having”and their conjugates mean “including but not limited to”.

The term “consisting of” means “including and limited to”.

As used herein, the singular form “a”, “an” and “the” include pluralreferences unless the context clearly dictates otherwise.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment, and the abovedescription is to be construed as if this combination were explicitlywritten. Conversely, various features of the invention, which are, forbrevity, described in the context of a single embodiment, may also beprovided separately or in any suitable sub-combination or as suitable inany other described embodiment of the invention, and the abovedescription is to be construed as if these separate embodiments wereexplicitly written. Certain features described in the context of variousembodiments are not to be considered essential features of thoseembodiments, unless the embodiment is inoperative without thoseelements.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims.

All publications, patents and patent applications mentioned in thisspecification are herein incorporated in their entirety by referenceinto the specification, to the same extent as if each individualpublication, patent or patent application was specifically andindividually indicated to be incorporated herein by reference. Inaddition, citation or identification of any reference in thisapplication shall not be construed as an admission that such referenceis available as prior art to the present invention. To the extent thatsection headings are used, they should not be construed as necessarilylimiting.

In addition, any priority document(s) of this application is/are herebyincorporated herein by reference in its/their entirety.

What is claimed is:
 1. A method of curing waste generated by an additivemanufacturing system, the method comprising: delivering said waste to acontainer via one or more waste nozzles; providing relative movement ofone or more container covers between an open position for delivery ofsaid waste by said one or more waste nozzles, and a closed position forshielding said one or more waste nozzles from radiation; and providingcuring radiation via one or more curing sources for curing said waste.2. The waste curing method of claim 1, comprising providing curingradiation for curing said waste after a predetermined amount of saidwaste has been delivered.
 3. The waste curing method of claim 2, whereinsaid predetermined amount of said waste comprises at least one of aweight of said waste and a height of said waste in said container. 4.The waste curing method of claim 2, comprising introducing a time delaybetween delivery of said predetermined amount of waste into saidcontainer and said providing of said curing radiation.
 5. The wastecuring method of claim 2, comprising operating said curing sources forat least the amount of time needed to cure the predetermined amount ofwaste material delivered in each delivery cycle.
 6. A process of curingof waste material comprising: feeding via one or more waste nozzles anamount of waste material generated by an additive manufacturing systeminto a waste container; halting waste feeding once a predeterminedamount of waste material has been fed into the waste container;introducing a time delay to allow dripping of waste material from saidone or more waste nozzles; shielding said waste nozzles from curingenergy; introducing a time delay to allow for the waste material tospread within the container; and initiating and providing curing energyfor at least the amount of time needed to cure the predetermined amountof waste material.
 7. The process of claim 6, wherein the waste materialis pumped or jetted into said waste container via said one or more wastenozzles, and said predetermined amount of waste is determined accordingto a number of pumping operations or a number of waste jettingoperations.
 8. The process of claim 6, wherein said predetermined amountof waste is gauged by a change in weight of said waste and/or a changeof height of said waste material in said container.
 9. The processaccording to claim 6, wherein a rate of waste feeding and curing isabout 120-400 g per hour.